In vehicle design, occupant safety is becoming increasingly important. To that end, vehicle safety systems and vehicle structure play a significant role. As a general proposition, when a moving vehicle is abruptly stopped (i.e., from contact with a stationary object or another vehicle), the forward and/or rearward momentum and associated forces are transferred to the vehicle occupants by way of vehicle structure and associated components. To minimize the effects of such forces on vehicle occupants, vehicle safety systems work in conjunction with energy management devices to transfer energy generated by the vehicle impact generally to the structure of the vehicle and away from the vehicle occupants.
Safety systems commonly work in conjunction with vehicle structure to transfer impact forces and divert the associated energy away from the vehicle occupants and into the vehicle structure. Modern vehicle safety systems commonly include a variety of energy management devices such as seatbelts and airbags to help protect a passenger in the event of an impact or accident. Such systems are typically designed to work together with sensors and other structural elements such as door beams, side sill sections, and body panels to improve overall vehicle safety and provide the best possible protection for vehicle occupants. More particularly, such systems act to gradually decelerate the occupants with the vehicle structure to dissipate the forces away from the occupants and into the vehicle structure.
Such impact forces are commonly absorbed by the vehicle structure through deformation of steel and other structural components. In an effort to effectively transmit impact forces to the vehicle structure, vehicle safety systems are implemented to safely transmit the force from a moving occupant (i.e., an occupant moving forward and/or rearward relative to a vehicle structure) to the vehicle structure via an energy management device such as a seatbelt or an airbag. More particularly, the forces associated with an occupant moving relative to the vehicle are safely and controllably transmitted to the vehicle structure via a seatbelt or an airbag such that the structure, as opposed to the occupant, can manage the energy.
Energy management devices, such as airbags and seatbelts, are commonly designed for use in conjunction with one another to transfer impact forces to the associated vehicle structure. Airbags transmit a force received by a moving occupant to the vehicle structure, while seatbelts transmit similar forces to the vehicle structure via a vehicle floor pan or vehicle seat, depending on the particular application. As can be appreciated, such vehicle seats receive the impact force from one or both of the airbag and seatbelt to dissipate energy safely to the vehicle structure, thereby protecting the vehicle occupants.
In addition to the aforementioned safety systems, vehicle seats also play a significant role in occupant protection. As can be appreciated, vehicle seats are commonly designed to work with safety systems and energy management devices to divert impact forces into the vehicle structure and away from vehicle occupants.
Conventional seat assemblies commonly include a seatback pivotably supported by a seat bottom and a recliner mechanism. The recliner mechanism is disposed generally between the seatback and the seat bottom and selectively positions the seatback relative to the seat bottom. In this manner, the ability of the seatback to absorb and transfer forces to a vehicle structure includes at least two components. First, the overall strength of the seatback structure should be of sufficient rigidity to receive a force from an occupant and transfer the associated force to the vehicle structure, and second, the recliner mechanism should be able to transmit such forces from the seatback to the seat bottom, which may include a cushion and an adjuster, and associated vehicle structure. In this regard, interaction between the occupant and the seatback plays a role in energy management during an impact event.
To ensure adequate engagement with a vehicle occupant, conventional vehicle seats commonly include a head restraint assembly. Typical head restraint assemblies are disposed at an opposite end of the seatback from the recliner mechanism and support the occupant's head during a rearward and/or rearward offset impact event. Such head restraint assemblies typically provide the occupant with the ability to adjust the position of the head restraint relative to the seatback, so as to provide each individual occupant with a desirable safe and comfortable head restraint position.
Today's design accommodates both tall and short persons. If a head restraint supports tall persons with an angled seat back then short persons with a more vertical seat back angle will have the head restraint pushing their head forward. The distance between a person's head and the head restraint is an important cause of whiplash injuries.
As can be appreciated, such an adjustment provides the occupant with the ability to adjust the head restraint so as to increase the safety criteria and comfort of the seat assembly under normal driving conditions both axially (i.e., up and down) and in a fore-aft direction. In addition, the head restraint assembly provides the occupant with a constantly safe and comfortable head to head restraint distance in response to all rotation or reclining positions of the seatback relative to the seat bottom.
An automatic forward adjustment of the head restraint upon rearward recline of the seatback and an automatic rearward adjustment of the head restraint upon forward recline of the seatback relative to the seat bottom helps to ensure that the occupant's head is in close proximity to the head restraint at all times for both tall and short occupants. Specifically, during a rearward impact situation, automatic positioning of the head restraint in such a fashion creates an immediate support of the occupant's head which will reduce and/or eliminate neck injuries during a rearward impact situation, as well as provide the occupant with a more comfortable driving position. Under a rear impact event, positioning the head restraint in proximity to the occupant's head encourages the occupant to engage the head restraint shortly after the initial impact, thereby quickly and efficiently transmitting the impact energy from the occupant's head into the vehicle seat. As previously discussed, such energy management allows the seat assembly and associated vehicle structure to dissipate the impact force and protect the occupant.